System and method for over under sensor packaging

ABSTRACT

An embodiment device includes a body structure having an interior cavity, a control chip disposed on a first interior surface of the interior cavity, and a sensor attached, at a first side, to a second interior surface of the interior cavity opposite the first interior surface. The sensor has a mounting pad on a second side of the sensor that faces the first interior surface, and the sensor is vertically spaced apart from the control chip by an air gap, with the sensor is aligned at least partially over the control chip. The device further includes an interconnect having a first end mounted on the mounting pad, the interconnect extending through the interior cavity toward the first interior surface, and the control chip is in electrical communication with the sensor by way of the interconnect.

TECHNICAL FIELD

The present invention relates generally to a system and method for anover-under sensor package, and, in particular embodiments, to a systemand method for packaging a sensor and associated control chip in avertical arrangement with the sensor spaced apart from the control chipin a shielded enclosure.

BACKGROUND

Generally, microelectrical mechanical system (MEMS) sensor devicesoperate on physically sensible environmental conditions. For example,MEMS devices may sense sound, air pressure, motion, or the like. MEMSdevices are generally simple sensor devices that generate a rawelectrical signal. MEMS sensors, such as MEMS microphones, have amovable membrane that reacts to pressure waves in air in an interiorcavity of the MEMS microphone to generate the electrical signal. A MEMSdevice package frequently includes a control chip, such as anapplication specific integrated circuit (ASIC), to manage the MEMSsensor device, read the raw data signal from the MEMS sensor device, andconvert the data signal into a desired data format. In some sensordevice packages, the MEMS sensor device and the control chip aredisposed in a cavity of the sensor device package.

SUMMARY

An embodiment device includes a body structure having an interiorcavity, a control chip disposed on a first interior surface of theinterior cavity, and a sensor attached, at a first side, to a secondinterior surface of the interior cavity opposite the first interiorsurface. The sensor has a mounting pad on a second side of the sensorthat faces the first interior surface, and the sensor is verticallyspaced apart from the control chip by an air gap, with the sensor isaligned at least partially over the control chip. The device furtherincludes an interconnect having a first end mounted on the mounting pad,the interconnect extending through the interior cavity toward the firstinterior surface, and the control chip is in electrical communicationwith the sensor by way of the interconnect.

An embodiment device includes a substrate having a first contact pad, asidewall, and a lid attached to the substrate by the sidewall, where thelid is separated from the substrate by an interior cavity that isbounded by the sidewall, the lid and the substrate. The device furtherincludes a control chip disposed on the substrate and extending from thesubstrate into the interior cavity, with the control chip in electricalcommunication with the first contact pad. A sensor is attached, at afirst side, to the lid, with the sensor extending from the lid into theinterior cavity, and with the sensor having a mounting pad. The sensoris vertically spaced apart from the control chip by an air gap, andwherein the sensor is aligned at least partially over the control chip.The device further has an interconnect having a first end mounted on themounting pad, with the interconnect extending through the interiorcavity and making electrical contact, at a second end of theinterconnect opposite the first end, with the first contact pad, wherethe interconnect is spaced apart from the sidewall.

An embodiment method includes attaching a first side of a sensor to afirst side of a lid, with the sensor having a contact pad disposed on asecond side of the sensor opposite the first side, providing aninterconnect on the contact pad, where a first end of the interconnectis attached to the contact pad, and wherein the interconnect extendsaway from the contact pad, attaching a control chip to a first side of asubstrate and electrically connecting the control chip to a landing paddisposed at the first side of the substrate, and affixing the lid overthe substrate, wherein the affixing forms an interior cavity between thelid and the substrate. After the affixing, the sensor and the controlchip each extend into the interior cavity and an air gap is providedbetween the sensor and the control chip, and, after the affixing, theinterconnect extends through the interior cavity, and a second end ofthe interconnect makes electrical contact with the landing pad.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawings, in which:

FIGS. 1A-1C illustrate formation of a first portion of a sensor packageaccording to some embodiments;

FIGS. 2A-2D illustrate formation of a second portion of a sensor packageand assembly of the sensor package according to some embodiments;

FIG. 3 is a flow diagram illustrating a method for forming a sensorpackage according to some embodiments;

FIGS. 4A-4C illustrate formation of a first portion of a shielded sensorpackage according to some embodiments;

FIGS. 5A-5H illustrate formation of a second portion of a shieldedsensor package, and mounting of the first portion on the second portionaccording to some embodiments;

FIG. 6 is a flow diagram illustrating a method for forming a shieldedsensor package according to some embodiments;

FIG. 7 illustrates a shielded sensor package with an enclosed backvolume according to some embodiments; and

FIGS. 8A-8C illustrate various lid and port arrangements according tosome embodiments.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Illustrative embodiments of the system and method of the presentdisclosure are described below. In the interest of clarity, all featuresof an actual implementation may not be described in this specification.It will of course be appreciated that in the development of any suchactual embodiment, numerous implementation-specific decisions may bemade to achieve the developer's specific goals, such as compliance withsystem-related and business-related constraints, which will vary fromone implementation to another. Moreover, it should be appreciated thatsuch a development effort might be complex and time-consuming but wouldnevertheless be a routine undertaking for those of ordinary skill in theart having the benefit of this disclosure.

Reference may be made herein to the spatial relationships betweenvarious components and to the spatial orientation of various aspects ofcomponents as the devices are depicted in the attached drawings.However, as will be recognized by those skilled in the art after acomplete reading of the present disclosure, the devices, members,apparatuses, etc. described herein may be positioned in any desiredorientation. Thus, the use of terms such as “above,” “below,” “upper,”“lower,” or other like terms to describe a spatial relationship betweenvarious components or to describe the spatial orientation of aspects ofsuch components should be understood to describe a relative relationshipbetween the components or a spatial orientation of aspects of suchcomponents, respectively, as the device described herein may be orientedin any desired direction.

The increasing complexity of electronic systems has given rise torequirements for ever increasing functionality in those electronicsystems and decreasing size in the components used for the systems. Inparticular, personal electronic devices have an increasing number ofmicrophones in order to detect sound in a variety of device orientationsand additional sensors for new features. As the number of sensorsincreased, the space allocated to each sensor decreases. Embodiments ofthe disclosed sensor packaging arrangement provide a system and methodfor packaging a sensor and control chip vertically within a sensorpackage, reducing package size and increasing reliability andsensitivity. In some embodiments, the sensor is disposed on a firstinterior surface of a package cavity and the control chip is disposed ona second interior surface of the package cavity opposite the firstinterior surface. The sensor is connected to the control chip by one ormore conductive connections that extend through the cavity. In someembodiments, the sensor is connected to the control chip by, forexample, wirebond elements. The wirebond elements may be applied to thesensor before the package is enclosed. Thus, the sensor is connected tothe control chip when the sensor is affixed over the control chip duringfinishing of the package, with the wirebond elements extending throughthe package cavity to connect the sensor control chip to the sensor.

The vertical arrangement of the sensor and control chip permits asmaller device package footprint than, for example, a side-by-sidearrangement. Additionally, providing the control chip and sensor asseparate elements avoids limitations imposed by differences in MEMS andintegrated circuit production technology, where either the control chipor the sensor may differ from the other by having smaller features,different process types, different substrates, different sizes orthicknesses, different coefficients of thermal expansion (CTEs), or thelike. Additionally, providing the sensor separately from the controlchip avoids drift in, for example, high resolution pressure sensorscaused by thermal-mechanical stress induced by the control chip elementsin a system-on-chip arrangement. The sensor may be disposed on a lidmade of a material with a CTE matched to that of the sensor, and the lidmay be configured to minimize the effect of lid thermal expansion on thesensor.

FIGS. 1A-1C illustrate formation of a first portion of a sensor packageaccording to some embodiments. FIG. 1A illustrates lids 101 for sensorpackages according to some embodiments. The first portion, or topportion, of a sensor package may include a lid 101 where a sensor willbe disposed. In some embodiments, the lid 101 may have one or more sideportions 109 that at least partially define a lid cavity 103. The lid101 has a mounting surface 121 in a lateral portion disposed between theside portions. The mounting surface 121 faces the lid cavity 103.

In some embodiments, the lids 101 are formed from a polymer, a metal oranother material. The lids 101 may, for example, be formed by molding apolymer using a mold, by stamping or pressing a polymer or metal sheetinto a lid form, by milling, etching or otherwise removing material froma larger blank to form the lid, by additive formation, such as threedimensional (3D) printing, selective laser sintering (SLS), or the like.For sensor packages that sense environmental conditions, the lids 101may have ports 105 providing an opening from the exterior of the sensorpackage to an interior cavity of the sensor package. In someembodiments, the port 105 is disposed in the lateral portion of the lid101 between the side portions 109, and extends through the lid 101 fromthe lid cavity 103 to the exterior of the lid 101. In other embodiments,the port 105 may be disposed in a side portion 109 of the lid 101, forexample, for a pressure sensor. In yet other embodiments, the lid 101may have multiple ports 105 in one or both of the lateral portions orthe side portions 109 of the lid 101. Furthermore, the device may havemultiple ports, and the sensor may cover one or more of the of the portsand not cover some of the ports. The multiple ports may be differentsizes difference shaped or vary from each other in another manner,permitting tuning of sensor and device performance. Air, gases,particulates, and the like to be sensed are able pass through the port105 for sensing by a sensor disposed within the lid cavity 103. In someembodiments, the port 105 is disposed in about the center of the lid101, and in other embodiments, the port 105 is disposed closer to one ofthe side portions 109 than to another side portion 109. In yet anotherembodiment, the port 105 includes multiple openings through the lid 101.While the lids 101 illustrated in FIG. 1A are shown having first lid 101with a first port 105 that is offset from the center of the lid 101, anda second lid 101 having a port 105 that is substantially centered in thelid 101, the embodiment lids 101 are shown to illustrate a process forforming sensor packages with different port arrangements and are notlimited to such an arrangement. Multiple lids 101 may be processed in abatch, and the lids 101 may have ports 105 positioned in a sameposition, or in different positions during processing. Additionally, insome embodiments, the lid 101 may be formed without a port, for example,in a radiation sensor package where air, particulate or gaseousmaterials are not required for sensing.

FIG. 1B illustrates mounting of sensors 111 and 113 in the lids 101according to some embodiments. In some embodiments, a sensor 111 and 113is affixed to an interior surface of the lid 110. The sensor 111 and 113may be attached to the mounting surface 121 of the lid 101 using, insome embodiments, die attachment film (DAF). In other embodiments, thesensor 111 and 113 is attached using a mechanical retaining structuresuch as a pin, clip, screw, or other structure, using an adhesive, glue,or the like. Each sensor 111 and 113 may have one or more contact pads115 disposed on a surface of the sensor 111 and 113. The contact pads115 are connected to circuitry in the sensors 111 and 113, permitting acontrol chip (not shown) to send and receive signals with the sensors111 and 113. In some embodiments, the contact pads 115 are disposed on atop side of the sensors 111 and 113, opposite the sensor 111 and 113from the surface on which the sensor 111 and 113 is mounted.

In some embodiments, the sensor 111 may be attached to the interior ofthe lid 101 so that the sensor 111 is laterally spaced apart from port105, and in other embodiments, the sensor 113 may be attached to theinterior of the lid 101 so that the sensor 113 is aligned over, orcovers, the port 105. The arrangement of the sensors 111 and 113 inrelation to the ports 105 may be determined by the type of sensor 111and 113. For example, a sensor 111 may be a top sensing sensor having asensing side on the top surface of the sensor 111. A top sensing sensoris may be spaced apart from the port 105 so that air or environmentalmaterial moving through the port 105 is unimpeded to the top surface ofthe sensor 111. In another example, a sensor 113 may be a “bottomsensing sensor,” and may have a sensor cavity 125 that is aligned overthe port 105. Aligning the bottom sensing sensor over the port 105permits air or environmental material to move directly through the port105, and through the sensor cavity 125, to the bottom surface of thesensor 113.

FIG. 1C illustrates mounting of interconnects 123 according to someembodiments. In some embodiments, interconnects 123 are formed on thecontact pads 115 of the sensors 111 and 113. The interconnects 123 may,in some embodiments, be formed as stud bumps using a wirebond processwhere a wirebonding machine bonds a first end of a wire to the contactpads 115, using, for example, a ball-bond. The interconnects 123 are aconduct material, and in some embodiments, may be formed from copperwire, gold wire, aluminum wire, and may be plated, doped or otherwisealloyed to customize the interconnect 123. The wirebonding machine formsa ball at the end of an exposed wire using, for example, an electricflame-off, and may weld, fuse or otherwise attach the ball end of theinterconnect to the contact pad 115 using, for example, heat, pressure,and/or ultrasonic vibration. After the ball end of the wire is attachedto the contact pad 115, the wirebonding machine may cut the wire to forma second end of the interconnect 123. After the interconnect 123 isformed, the interconnect 123 has a first end bonded to the contact pad115, and extends into the lid cavity 103 away from the sensor 111 and113 and the mounting surface 121 of the lid 101. In some embodiments, asecond end of the interconnect 123 is about level with the ends of theside portions 109 of the lid so that the lid, with the interconnect 123,may be mounted on a substantially flat surface.

In other embodiments, the interconnect 123 is a solder ball, a solderball with a supporting structure, a preformed structure that is placedon the contact pad, a printed structure or structure that is formed inplace on the contact pad 115. In some embodiments, solder paste, solder,conductive adhesive, or another conductive material is disposed on thecontact pads 115, and the interconnect 123 may be bonded to the contactpad 115 by reflow, curing, or the like. The interconnects 123 may alsobe attached to the contact pads 115 prior to the sensors 111 and 113being attached to the lid 101.

FIGS. 2A-2D illustrate formation of a second portion of a sensor packageand assembly of the sensor package according to some embodiments. FIG.2A illustrates a package base 201 for a sensor package according to someembodiments. The package base 201 may have one or more landing pads 213and via pads 211 disposed on a top side or first surface of a substrate205. The substrate 205 may have a body that is an insulating materialsuch as a polymer, fiberglass, an oxide, ceramic, or the like. The viapads 211 may be conductive and connected to a via 207 formed from aconductive material, and may extend through the substrate 205 to apackage mounting pad 209 disposed on a bottom side or second surface ofthe substrate 205. The substrate body electrically insulates the landingpads 213, the via pads 211, vias 207 and package mounting pads 209 fromeach other. The vias 207 or landing pads 213 may extend laterallythrough, or on, the substrate 205 by way of metallization layers or thelike disposed in the body of the substrate 205, permitting multiplelanding pads and vias to be redirected and cross each other in differentlayers without being in electrical contact.

In some embodiments, one or more stopper pads 215 are formed on the topside or first surface of the substrate 205. The stopper pads 215 may beformed from a conductive material, and in some embodiments, are formedas part of a metal layer with the landing pads 213 and the via pads 211,by metal deposition and patterning, printing of a conductive material,or the like. The stopper pads 215 may have top surfaces that aresubstantial level or coplanar with top surfaces of the landing pads 213or via pads 211. The stopper pads 215 may be formed to encircle the areaon which control chips will be mounted to form a contiguous region onwhich a lid may be mounted

FIG. 2B illustrates attachment of a wirebonded control chip 221according to some embodiments. In some embodiments, a package includes awirebonded control chip 221. The control chip 221 may be an ASIC,communications device, an interface device, or the like, and may havecircuitry that controls, or reads a sensor. The control chip 221 isattached to the substrate 205 by a die attachment structure 217 such asDAF, adhesive, tape, or the like. In other embodiments, the control chip221 is attached to the substrate 205 with a mechanical retainer such asa clip, socket, screw, or the like. The control chip 221 has one or morecontrol bond pads 223 disposed on a top side, and is electricallyconnected to a via pad 211 or a landing pad 213 or the like usingwirebond connections 225.

FIG. 2C illustrates attachment of a pad mounted control chip 221according to some embodiments. Conductive connectors 235 may be appliedto one or more of the via pads 211 and landing pads 213. In someembodiments, the conductive connectors 235 are solder, solder paste, aconductive adhesive, conductive glue, or the like. Additionally, theconductive connectors 235 may also be applied to the stopper pads 215,or a nonconductive adhesive material may be applied to the stopper pads215 for subsequent mounting of a lid 101 on the stopper pads 215. Thepad mounted control chip 231 is attached to a via pad 211 or landing padby the conductive connectors 235.

In some embodiments, a package includes a control chip 221 mounted byway of mounting pads 233 that are disposed on a bottom side of thecontrol chip 231. While the package base 201 illustrated in FIG. 2C isshown with a wirebonded chip 221 and a pad mounted control chip 231, thedifferent types of control chips are shown purely for illustrativepurposes, and is not intended to be limiting. A package base 201 may beformed with any number of control chips of the same type, or may havedifferent types of control chips.

FIG. 2D illustrates mounting of lids 101 on the package base 201. Endsof the side portions 109 of the lids 101 are attached to the packagebase 201. In some embodiments, the side portions 109 are affixed to thestopper pads 215 by the conductive connectors 235. After attachment ofthe lids 101 to the package base, 201, the control chips 231 and 221 aredisposed within the lid cavity 103, which creates an interior cavity forthe package, with the interior cavity bounded by the lid 101 and thesubstrate 205. Since the interior cavity of the package is created byseparation of the mounting surface 121 from the top surface of thesubstrate 205, the interior cavity may have a volume that is determinedby the length and angle of the side portions 109 of the lid 101,allowing customization of the interior cavity volume according to therequirements of the sensors 111 and 113. Thus, a sensor package may havea body structure that includes the substrate 205 and lid 101, and thathas an interior cavity that includes the lid cavity 103. The sensor 111and 113 is disposed on a first interior surface of the interior cavity,and the control chip 221 and 231 is disposed on a second interiorsurface of the interior cavity and physically separated from the sensorby an air gap. The sensor 111 and 113 is electrically connected to thecontrol chip 221 and 231 by an interconnect 123 that extends across theair gap from the sensor 111 and 113 to a landing pad 213 on thesubstrate 205.

The interior cavity of the sensor package may act as a back volume,while the sensor cavity 125 may act as a front volume for a sensor 113disposed over the port 105. The front volume, or sensor cavity 125,provides an opening for air, pressure waves, or other environmentalmaterial to reach the active or measurement elements of the sensor 113.For sensors that are microphones, the sensor cavity 125 may be a frontvolume that creates resonance in air interacting with the port 105 andthe sensor cavity 125, increasing the sensitivity of the microphone. Alarger volume of air in the back chamber, or lid cavity 103, makes iteasier for the membrane or sensing element of the sensor 113 to move inresponse to sound waves, which improves the sensitivity of, for example,a sensor microphone, and leads to higher signal-to-noise ratio (SNR). Alarge back volume also improves, for example, a sensor microphone lowfrequency response.

The interconnects 123 are secured to the landing pads 213 by theconductive connectors 235, electrically connecting the respectivesensors 111 and 113 to a respective control chip 221 and 231 through thelanding pads 213. In some embodiments, the sensors 111 and 113 may atleast partially overlap the respective control chip 221 and 231 in alateral direction while being spaced part in a vertical direction. Thus,an air space or air gap is provided between the sensors 111 and 113 andthe respective control chip 221 and 231. The air gap provides physicalseparation between the sensors 111 and 113 and the respective controlchip 221 and 231 to reduce stress transferred to the sensor 111 and 113while acting as a back volume for the sensor 111 and 113. In someembodiments, a sensor 113 may completely overlap the control chip 221 inthe lateral direction, while being spaced apart from the control chip221 in the vertical direction. Thus, the sensor 113 may have lateralextents that extend laterally past lateral extents of the control chip221.

In some embodiments, the interconnects 123 may extend from the sensor111 and 113 to a contact pad on a respective control chip 221 and 231,eliminating the need for a landing pad. In some embodiments, aninterconnect 123 may be formed on an interior surface of the lid 101 andmay extend to a contact pad on a control chip 221 and 231 or landing pad213 on the substrate 205, for example, to ground the lid 101. In otherembodiments, the sensors 111 and 113 may be electrically connected tothe control chips 221 and 231 by conductive lines formed in or on thelids 101, and which connect to elements of the stopper pads 215 or toother conductive elements on the substrate 205.

FIG. 3 is a flow diagram illustrating a method 301 for forming a sensorpackage according to some embodiments. In block 303, a lid is provided,and in block 305, a sensor is attached to an interior surface of thelid. In block 307, one or more interconnects are formed.

In block 309, a substrate is provided, and in block 311, control chipsare attached and/or connected to the substrate. In some embodiments, thecontrol chips may be mounted on the substrate and wires may be used toelectrically connect the contact pads of the control chips to contactpads, such as via pads or landing pads, on the substrate. In block 313,one or more conductive connectors are applied to pads on the substrate,and in some embodiments, the conductive connectors are applied tostopper pads, landing pads, or via pads. Additionally, in someembodiments, the conductive connectors may be applied before the controlchips are connected, so that pad mounted control chips are affixed tocontact pads on the substrate by the conductive connectors. In block315, the lid with attached sensor is flipped and bonded to thesubstrate.

FIGS. 4A-4C illustrate formation of a first portion 413 of a shieldedsensor package according to some embodiments. FIG. 4A illustrates aframe 401 for a package according to some embodiments. The frame 401includes portions that form one or more lids in an assembled shieldedsensor package. The frame 401 may have one or more ports 405 that extendthrough the frame 401. The frame 401 may also have bleed stop ridges 403formed on one side of the frame 401. The bleed stop ridges 403 may beraised areas on the top surface of the frame 401, and each bleed stopridge 403 may be formed to surround a respective port 405, and provide aphysical barrier that prevents material applied to the top surface ofthe lid 101 from bleeding, or running outside of the bleed stop ridges403.

In some embodiments, the frame 401 is the structure used to form lidsused in a sensor package, and may be formed from a conductive materialto provide electromagnetic interference (EMI) shielding for the package.In some embodiments, the frame 401 may be made from copper, gold,aluminum, or another metal or alloy, and may be formed by molding, bychemical or plasma etching, by milling, by stamping, or by anotherformation process. In other embodiments, the frame 401 may be made froma conductive material, such as a molding compound having conductivematerial disposed therein, or a conductive polymer such as an epoxy,molding compound, or the like.

FIG. 4B illustrates mounting of sensors 407 on the frame 401 to form thefirst portion 413 of the shielded sensor package according to someembodiments. An adhesive 411 such as a glue, epoxy, DAF, or the like, isdeposited on the top surface of the frame 401 within the bleed stopridges 403, which contain the adhesive 411. The bleed stop ridges 403prevent the adhesive 411 from flowing between areas designated fordifferent lids or packages.

In some embodiments, sensors 407 are mounted on the adhesive 411 so thatthe sensors 407 are affixed to the top surface of the frame 401. In someembodiments, each of the sensors 407 may be attached to the frame 401spanning a port 405, for example, for a top port sensor package. Each ofthe sensors 407 may have a sensor cavity 415 or the like that acts as afront chamber or front volume for the sensor 407. In other embodiments,the sensors 407 may be laterally offset from the ports 405 or formedbetween multiple ports, and in bottom port arrangements, the lid may beformed without ports.

FIG. 4C illustrates mounting of interconnects 421 and 423 on the firstportion 413 of the shielded sensor package according to someembodiments. The interconnects 421 and 423 may include frameinterconnects 423 that are mounted on, and in electrical contact withthe frame 401. In some embodiments, the frame interconnects 423 aremounted on the bleed stop ridges 403, or on another exposed portion ofthe frame 401, and may provide a ground connection for the frame 401 orlids. The interconnects 421 and 423 may also include sensorinterconnects 421 that are mounted on sensor landing pads 409 disposedon a top side of the sensors 407. The interconnects 421 and 423 may bewirebond structures formed using a wirebond machine, and may be formedas discussed above. The interconnects 421 and 423 have a first enddisposed on the frame 401 or on the sensor 407, and extend away from theframe 401. Second ends of the interconnects 421 and 423 are opposite thefirst ends of the interconnects 421 and 423 that are mounted to theframe 401 or sensor landing pads 409. In some embodiments, the secondends of the interconnects 421 and 423 are substantially level orcoplanar to facilitate mounting of a lid that is formed from part of thefirst portion 413. In other embodiments, the interconnects 421 and 423are solder balls, solder balls with supporting structures, preformedstructures that are placed on the contact pad, printed structures orstructures that are formed in place on the frame 401 or sensor landingpads 409.

FIGS. 5A-5F illustrate formation of a second portion of a shieldedsensor package according to some embodiments. FIG. 5A illustrates asecond portion 501 of a shielded sensor package according to someembodiments. The second portion 501 may have one or more pads 505disposed at a surface of a substrate 513, and may be interconnected byone or more metal lines 507 on the substrate 513 or in a substrate body503.

FIG. 5B illustrates formation of sidewalls 509 on the second portion 501according to some embodiments. In some embodiments, the sidewalls 509are formed on the substrate body 503, and in other embodiments, thesidewalls 509 may be formed on a stopper pad, oxide or sealing layer, orthe like, that is disposed on a surface of the substrate 513.

In some embodiments, the sidewalls 509 are formed from an elastomermolding compound, with the sidewalls 509 comprising a conductivematerial so that the sidewall 509 are conductive. Conductive sidewallsprovide EMI shielding for sensors 407 and control chips 515 and 529disposed within an interior cavity 511 bounded by the sidewalls 509 andsubstrate 513. In some embodiments, the conductive material is aconductive filler disposed throughout the material forming the sidewall509. For example, the conductive material may be carbon (C), such ascarbon black, or may be passivated aluminum (Al), silver plated Al(Ag/Al), Ag plated copper (Al/Cu), Ag plated glass, Ag plated nickel(Ag/Ni), Ni coated carbon, Ni, Ag, Cu, or another conductive material.The elastomer material may be a molding compound, epoxy, polymer, or thelike. In other embodiments, the sidewalls 509 may be a plated elastomer,where the elastomer is formed and then plated with the conductivematerial.

The sidewall 509 may be formed by molding the sidewall in place, by 3Dprinting, by pre-forming the sidewall 509 and attaching the sidewall 509to the substrate 513, or another forming process. The sidewall 509 isformed to contiguously surround a die area and one or more of the pads505, and extend away from the substrate 513 to provide the interiorcavities 511.

FIG. 5C illustrates attachment of a control chip 515 according to someembodiments. The control chip 515 may be an ASIC, communications device,an interface device, or the like, and may have circuitry that controls,or reads a sensor. The control chip 515 is attached to the substrate 513by a die attachment structure 519 such as DAF, adhesive, tape, or thelike. In other embodiments, the control chip 515 is attached to thesubstrate 513 with a mechanical retainer such as a clip, socket, screw,or the like. The control chip 515 has one or more control chip bond pads517 disposed on a top side that faces away from the substrate 513.

FIG. 5D illustrates wirebonding of the control chip 515 to one or morepads 505 according to some embodiments. In some embodiments, the controlchip 515 is a wirebonded control chip and is electrically connected toone or more of the pads 505 using wirebond connections 523.

FIG. 5E illustrates attachment of a pad mounted control chip 529according to some embodiments. Conductive connectors 527 may be appliedto one or more of the pads 505. In some embodiments, a package includesa control chip 529 mounted by mounting pads 531 disposed on a bottomside of the control chip 529. The pad mounted control chip 529 isattached to pads 505 by the conductive connectors 527. While the secondportion 501 of the shielded sensor package illustrated in FIG. 5E isshown with a wirebonded control chip 515 and a pad mounted control chip529, the different types of control chips 515 and 529 are shown purelyfor illustrative purposes, and is not intended to be limiting.

FIG. 5F illustrates application of a lid connector 537 to the sidewalls509 according to some embodiments. The lid connector is disposed onsecond ends of the sidewalls 509, and may be a glue, DAF, epoxy, oranother adhesive or attachment structure.

FIGS. 5G-5H illustrate assembly of shielded sensor packages 541according to some embodiments. FIG. 5G illustrates attachment of thefirst portion 413 to the second portion 501. The first portion 413 isinverted and affixed to the second portion 501 by the lid connectors 537to enclose the interior cavity 511. Additionally, the interconnects 421and 423 are attached to the pads 505 of the second portion and affixedby the conductive connectors 527. In some embodiments, the top surfacesof the pads 505 are substantially level, so that the ends of theinterconnects 421 and 423 make consistent contact with respective pads505. In some embodiments, each of the interconnects 421 and 423 extendfrom the first portion 413 of the shielded sensor package 541 so that asecond end of each of the interconnects 421 and 423 is in electricalcontact with a different contact pad 505 on the surface of the substrate513. In other embodiments, one or more of the interconnects 421 and 423contacts a control chip bond pad 517, or another landing pad, contactpad, or the like. Thus, the sensor 407 may be connected to a respectivecontrol chip 515 and 529 by way of the sensor interconnects 421 whilethe sensor and respective control chip 515 and 529 are spaced apart.

The sidewalls 509 and frame 401 form a conductive shell providing EMIshielding for the enclosed control chips 515 and 529 and sensors 407. Insome embodiments, the substrate 513 also has a shielding layer (notshown), increasing the EMI shielding of the packages 541. Additionally,in the arrangement illustrated, the interior cavity 511 acts as a backvolume for the sensor 407, while the sensor cavity 415 acts as frontvolume.

After the first portion 413 is mounted on the second portion 501, thepackages 541 may be cured, reflowed, or the like to set, cure, or reflowthe lid connectors 537 and conductive connectors 527. The packages 541may also be mounted on a carrier 539 such as a tape or the like.

FIG. 5H illustrates singulation of the packages 541 according to someembodiments. The first portion 413 and second portion 501 of thepackages 541 are cut, for example, by die sawing, laser cutting, or thelike, to form cut region 543 and separate the individual package 541while maintaining the packages 541 on the carrier 539 for shipping andinstallation.

While the packages 541 are illustrated with the port 405 disposed in theframe 401, it should be understood that the packages 541 may be formedwith one or more ports 405 in other parts of the package 541, or with noport. For example, the package 5451 may be a bottom port package with aport extending through the substrate 513, or through a sidewall 509. Inother embodiments, the packages 541 may be formed without a port, forexample, for a radiation sensor or the like. In yet other embodiments,the package 541 may be formed with multiple ports which may be ofsimilar size and shape, or may differ in size or shape.

FIG. 6 is a flow diagram illustrating a method 601 for forming ashielded sensor package according to some embodiments. In block 603, alid is provided. In some embodiments, the lid is formed from aconductive material and is part of a frame or the like. In block 605, asensor is attached to the lid, and in block 607 interconnects areformed. In some embodiments, the interconnects are wirebond structuresthat have a first end mounted on the lid or on the sensor, with a secondend extending away from the lid. In other embodiments, the interconnectsare other rigid conductive structures, solder balls, or the like.

In block 609 a substrate is provided. In some embodiments, the substratehas one or more pads, and also has one or more metal lines disposed inthe body of the substrate connecting the pads to each other, or to padson an opposite side of the substrate.

In block 611, sidewalls are formed on the substrate. In someembodiments, the sidewalls have an embedded conductive material orconductive plating. In block 613, a control chip is mounted to thesubstrate and electrically connected to the pads of the substrate. Inblock 615, one or more conductive connectors are applied to the pads. Insome embodiments, the control chip may be pad mounted connected to thepads and affixed by the conductive connectors. In other embodiments, thecontrol chip may be a wirebonded control chip that is affixed to thesubstrate by a DAF, adhesive or the like, and electrically connected tothe pads by wirebond connections.

In block 617, a lid connector such as an adhesive, glue, DAF, conductivestructure or the like, is applied to the sidewalls, and in block 619,the lid is flipped and attached to the substrate by way of the lidconnector. In some embodiments, attaching the lid to the substrateincludes bringing the second ends of the interconnects into contact withthe pads on the substrate and the conductive connectors. Thus, after thelid is attached to the substrate, the sensors are spaced apart from thecontrol chip by an air gap, and are electrically connected to thecontrol chips by way of connectors spaced apart from the sidewalls andpassing through the interior cavity of the package. In block 621, thepackages are singulated by cutting between packages.

FIGS. 2D and 5G-5H illustrate top port packages, where the port isdisposed in the lid. However, the formation of the package according theembodiments is not limited to top port packages, as bottom port packagesmay also be formed with sensors stacked over, and spaced apart from, thecontrol chips. FIG. 7 illustrates a bottom port shielded sensor package701 with an enclosed back cavity 711 according to some embodiments. Thepackage 701 has a back volume portion 751 and a front volume portion753. The back volume portion 751 has first sidewalls 715 separating atop lid 713 from a center lid 707. The center lid 707 may have a port709 extending to the back cavity 711, which acts as a back volume for asensor 703 mounted over the port 709 on a bottom surface of the centerlid 707. The sensor 703 may be mounted on the bottom surface of thecenter lid 707 by way of a sensor attachment structure 721 such as aDAF, adhesive, epoxy, or the like. The center lid 707 is attached to thefirst sidewalls 715 by way of a first attachment structure 717 such asan adhesive, tape, epoxy, or the like. One or more lid interconnects 723may be formed on the center lid 707 and may extend through the frontcavity 705, and one or more sensor interconnects 725 may be mounted onmounting pads 727 of the sensor 703 and may extend through the frontcavity 705.

The front volume portion 753 has a substrate 745 with an external port739 passing from the exterior of the package 701 through the substrate745 to the front cavity 705. The substrate has one or more pads 729 andone or more metal lines 741 connecting the pads 729 to each other or toa mounting pad 743. A control chip 731 is mounted by conductiveconnectors 737 such as solder paste, solder balls, or the like. Theconductive connectors 737 connect mounting pads 733 on the control chip731 to one or more of the pads 729. The front volume portion 753 mayfurther have second sidewalls 735 formed on the substrate 745surrounding the control chip 731 to at least partially define the frontcavity 705.

The back volume portion 751 is mounted on the front volume portion 753by way of a second attachment structure 719 such as an adhesive, tape,epoxy, or the like. The second attachment structure 719 may be disposedon an end surface of the second sidewalls 735 to hold the center lid 707above the second sidewalls 735 with the sensor 703 aligned at leastpartially over the control chip 731 while maintaining a separation orair gap between the sensor 703 and the control chip 731 in the frontvolume. The lid interconnects 723 and sensor interconnects 725 extendthrough the front cavity 705 so that second ends of the interconnects723 and 725 make electrical contact with the pads 729 and are affixed tothe pads 729 by the conductive connectors 737. Thus, in someembodiments, the center lid 707, in some embodiments, may have a groundconnection to the control chip 731 provided by the lid interconnect 723,or, in other embodiments, to a mounting pad disposed on the bottom ofthe substrate 745. Similarly, in some embodiments, the sensor 703 may bein electrical contact with the control chip 731 by way of the sensorinterconnect 725.

In some embodiments, EMI shielding may be provided for the sensor 703and control chip 731 by the center lid 707 and the second sidewalls 735.The EMI shielding may be achieved, for example, by forming the centerlid from a conductive material, as described above, and forming thesecond sidewalls 735 with a conductive material, as described above. Insuch an embodiment, the top lid 713 and first sidewall 715 may be formedfrom an elastomer, polymer, epoxy, or the like and may be formed from anonconductive material since the sensor 703 and control chip 731 areenclosed in the conductive structure of the center lid 707 and secondsidewalls 735. In other embodiments, the first sidewall 715 and/or toplid 713 may be formed from, or with, a conductive material to provideadditional EMI shielding.

In some embodiments, the control chip 731, substrate 745 and pads 729and second sidewalls 735 may be produced or provided as described aboveto form the front volume portion 753. The sensor 703 and interconnects723 and 725 may also be attached to the center lid 707 as describedabove. The top lid 713 may be provided, and the first sidewalls 715 maybe formed on the top lid 713, with the center lid 707 subsequentlymounted on the first sidewalls 715 to form the back volume portion 751.The back volume portion 751 may then be mounted on the front volumeportion 753.

In other embodiments, the center lid 707 may be provided, and the firstsidewalls 715 may be formed on the center lid 707 by molding, or thelike, and the top lid 713 attached to the first sidewalls 715 to formthe back volume portion 751. The back volume portion 751 may then bemounted on the front volume portion 753.

FIGS. 8A-8C illustrate various lid and port arrangements according tosome embodiments. FIG. 8A illustrates a top port lid 801 with a port 805disposed in a middle region of the lid 801. A sensor mounting region 803overlies the port 805, so that a sensor disposed in the sensor mountingregion 803 covers, or is aligned with, the port 805.

FIG. 8B illustrates a top port lid 811 with a port 815 that is offsetfrom a center or middle region of the lid 811 according to someembodiments. Offsetting the port 815 towards a side of the lid 811permits space for a sensor mounting region 813 that is adjacent to theport 815. Thus, a sensor disposed in the sensor mounting region 813 isadjacent to, and nonaligned with, the port 815.

FIG. 8C illustrates a top port lid 821 with multiple ports 825 accordingto some embodiments. The lid 821 may have multiple ports 825 disposedaround a sensor mounting region 823, creating a stress reduction region829 in the lid 821. The stress reduction region 829 is connected theremainder of the lid 821 by bridge regions 827 between the multipleports 825. The use of the multiple port 825 reduces transmission of atleast a portion of the stresses introduced to the lid 821 by, forexample, thermal stress in the sidewalls of a package, to a sensormounted in the sensor mounting region 823. Having the multiple ports 825that form corners of the stress reduction region leaves portions of thelid 821 to expand, contract, or move without affecting the stressreduction region 829 and associated sensor. This is because the multipleports 825 at least partially decouple the edge of the lid 821 form thecenter of the lid 821. The multiple ports 825 serve a dual function,reducing stress on an associated sensor while permitting sensed air orenvironmental materials to pass through the lid 821.

An embodiment device includes a body structure having an interiorcavity, a control chip disposed on a first interior surface of theinterior cavity, and a sensor attached, at a first side, to a secondinterior surface of the interior cavity opposite the first interiorsurface. The sensor has a mounting pad on a second side of the sensorthat faces the first interior surface, and the sensor is verticallyspaced apart from the control chip by an air gap, with the sensor isaligned at least partially over the control chip. The device furtherincludes an interconnect having a first end mounted on the mounting pad,the interconnect extending through the interior cavity toward the firstinterior surface, and the control chip is in electrical communicationwith the sensor by way of the interconnect.

In some embodiments, the body structure includes a sidewall, a lid and asubstrate, where a surface of the substrate is the first interiorsurface, where a surface of the lid is the second interior surface, andwhere the lid is attached to the substrate by the sidewall. In someembodiments, the lid is formed from a first conductive material, thesidewall comprises a second conductive material, and the lid and thesidewall provide electromagnetic interference (EMI) shielding for thecontrol chip and the sensor. In some embodiments, the body structureincludes a lid and a substrate, a first surface of the substrate is thefirst interior surface, a second surface of the lid is the secondinterior surface, the lid has side portions that extend past the sensorand bound the interior cavity, and the lid is attached to the substrateat ends of the side portions. In some embodiments, the interconnect is awirebond interconnect, and the first end of the interconnect is a ballend.

An embodiment device includes a substrate having a first contact pad, asidewall, and a lid attached to the substrate by the sidewall, where thelid is separated from the substrate by an interior cavity that isbounded by the sidewall, the lid and the substrate. The device furtherincludes a control chip disposed on the substrate and extending from thesubstrate into the interior cavity, with the control chip in electricalcommunication with the first contact pad. A sensor is attached, at afirst side, to the lid, with the sensor extending from the lid into theinterior cavity, and with the sensor having a mounting pad. The sensoris vertically spaced apart from the control chip by an air gap, andwherein the sensor is aligned at least partially over the control chip.The device further has an interconnect having a first end mounted on themounting pad, with the interconnect extending through the interiorcavity and making electrical contact, at a second end of theinterconnect opposite the first end, with the first contact pad, wherethe interconnect is spaced apart from the sidewall.

In some embodiments, the interconnect is a wirebond interconnect, andthe first end of the interconnect is a ball end. In some embodiments,the lid is formed from a conductive material. In some embodiments, thesidewall comprises a conductive material and provides electromagneticinterference (EMI) shielding for the control chip and the sensor. Insome embodiments, the sidewall is a side portion of the lid. In someembodiments, the lid has a port disposed therein, and the sensor coversthe port. In some embodiments, the lid has a port disposed therein, andthe sensor is laterally spaced apart from the port. In some embodiments,the sensor is a microelectrical mechanical system (MEMS) microphone. Insome embodiments, the sensor has lateral extents that extend pastlateral extents of the control chip.

An embodiment method includes attaching a first side of a sensor to afirst side of a lid, with the sensor having a contact pad disposed on asecond side of the sensor opposite the first side, providing aninterconnect on the contact pad, where a first end of the interconnectis attached to the contact pad, and wherein the interconnect extendsaway from the contact pad, attaching a control chip to a first side of asubstrate and electrically connecting the control chip to a landing paddisposed at the first side of the substrate, and affixing the lid overthe substrate, wherein the affixing forms an interior cavity between thelid and the substrate. After the affixing, the sensor and the controlchip each extend into the interior cavity and an air gap is providedbetween the sensor and the control chip, and, after the affixing, theinterconnect extends through the interior cavity, and a second end ofthe interconnect makes electrical contact with the landing pad.

In some embodiments, after the affixing, the sensor is at least partlylaterally aligned over the control chip. In some embodiments, theproviding the interconnect comprises forming a wirebond interconnectwith the first end of the interconnect as a ball end. In someembodiments, the method further includes forming a sidewall on thesubstrate with a first end of the sidewall affixed to the substrate,where the sidewall is conductive, where the lid is formed from aconductive material, wherein the affixing the lid over the substratecomprises affixing the lid to a second end of the sidewall, and, afterthe affixing, the lid and sidewall provide electromagnetic interference(EMI) shielding for the control chip and the sensor. In someembodiments, the lid includes a side portion extending past the sensor,and where the affixing the lid over the substrate comprises affixing theside portion of the lid to the substrate. In some embodiments, the lidis a center lid disposed on a second package portion having a backvolume for the sensor, the center lid has a port extending from the backvolume through the center lid, the substrate is part of a first packageportion having first sidewalls disposed on the substrate, the affixingthe lid over the substrate includes affixing the second package portionto ends of the sidewalls of the first package portion, and the affixingforms the interior cavity as a front volume for the sensor.

While this invention has been described with reference to illustrativeembodiments, this description is not intended to be construed in alimiting sense. Various modifications and combinations of theillustrative embodiments, as well as other embodiments of the invention,will be apparent to persons skilled in the art upon reference to thedescription. It is therefore intended that the appended claims encompassany such modifications or embodiments.

1. A device, comprising: a body structure having an interior cavity; acontrol chip disposed on a first interior surface of the interiorcavity; a landing pad disposed on the first interior surface andelectrically connected to the control chip; a sensor attached, at afirst side, to a second interior surface of the interior cavity oppositethe first interior surface, the sensor having a mounting pad on a secondside of the sensor that faces the first interior surface, wherein thesensor is vertically spaced apart from the control chip by an air gap,and wherein the sensor is aligned at least partially over the controlchip; and an interconnect having a first end mounted on, and in directcontact with, the mounting pad, the interconnect extending through theinterior cavity toward the first interior surface, wherein all sidesurfaces of the interconnect are spaced apart from the interior surfacesof the interior cavity, wherein the side surfaces of the interconnectextend contiguously from the first end of the interconnect to a secondend of the interconnect and are exposed to the interior cavity, andwherein the second end of the interconnect is connected to the landingpad by a conductive connector in direct contact with the landing pad andthe second end of the interconnect; wherein the control chip is inelectrical communication with the sensor by way of the interconnect andlanding pad.
 2. The device of claim 1, wherein the body structureincludes a sidewall, a lid and a substrate, wherein a surface of thesubstrate is the first interior surface, wherein a surface of the lid isthe second interior surface, and wherein the lid is attached to thesubstrate by the sidewall.
 3. The device of claim 2, wherein the lid isformed from a first conductive material, wherein the sidewall comprisesa second conductive material, and wherein the lid and the sidewallprovide electromagnetic interference (EMI) shielding for the controlchip and the sensor.
 4. The device of claim 1, wherein the bodystructure includes a lid and a substrate, wherein a first surface of thesubstrate is the first interior surface, wherein a second surface of thelid is the second interior surface, and wherein the lid has sideportions that extend past the sensor and bound the interior cavity, andwherein the lid is attached to the substrate at ends of the sideportions.
 5. The device of claim 1, wherein the interconnect is awirebond interconnect, and wherein the first end of the interconnect isa ball end.
 6. A device, comprising: a substrate having a first contactpad; a sidewall; a lid attached to the substrate by the sidewall,wherein the lid is separated from the substrate by an interior cavitythat is bounded by the sidewall, the lid and the substrate; a controlchip disposed on the substrate and extending from the substrate into theinterior cavity, the control chip in electrical communication with thefirst contact pad; a landing pad disposed on the substrate andelectrically connected to the control chip; a sensor attached, at afirst side, to the lid, the sensor extending from the lid into theinterior cavity, the sensor having a mounting pad, wherein the sensor isvertically spaced apart from the control chip by an air gap, and whereinthe sensor is aligned at least partially over the control chip; and aninterconnect having a first end mounted on, and in direct contact with,the mounting pad, the interconnect extending through the interior cavityand making electrical contact, at a second end of the interconnectopposite the first end, with the first contact pad, wherein theinterconnect is spaced apart from side surfaces of the interior cavity,wherein side surfaces of the interconnect extend contiguously from thefirst end of the interconnect to a second end of the interconnect andare exposed to the interior cavity, and wherein the second end of theinterconnect is connected to the landing pad by a conductive connectorin direct contact with the landing pad and the second end of theinterconnect.
 7. The device of claim 6, wherein the interconnect is awirebond interconnect, and wherein the first end of the interconnect isa ball end.
 8. The device of claim 6, wherein the lid is formed from aconductive material.
 9. The device of claim 6, wherein sidewallcomprises a conductive material and provides electromagneticinterference (EMI) shielding for the control chip and the sensor. 10.The device of claim 6, wherein the sidewall is a side portion of thelid.
 11. The device of claim 6, wherein the lid has a port disposedtherein, and wherein the sensor covers the port.
 12. The device of claim6, wherein the lid has a port disposed therein, and wherein the sensoris laterally spaced apart from the port.
 13. The device of claim 6,wherein the sensor is a microelectrical mechanical system (MEMS)microphone.
 14. The device of claim 6, wherein the sensor has lateralextents that extend past lateral extents of the control chip. 15-20.(canceled)
 21. A device, comprising: a substrate; a lid affixed over thesubstrate and forming an interior cavity between the lid and thesubstrate; a sensor attached, at a first side, to a first side of thelid, the sensor having a contact pad disposed on a second side of thesensor opposite the first side; an interconnect disposed on the contactpad, wherein a first end of the interconnect is directly attached to thecontact pad, wherein the interconnect extends away from the contact padthrough the interior cavity and extends to a landing pad disposed at afirst side of the substrate, wherein all side surfaces of theinterconnect are spaced apart from interior surfaces of the interiorcavity, wherein the side surfaces of the interconnect extendcontiguously from the first end of the interconnect to a second end ofthe interconnect and are exposed to the interior cavity, and wherein thesecond end of the interconnect makes electrical contact with the landingpad and is connected to the landing pad by a conductive connector indirect contact with the landing pad and the second end of theinterconnect; and a control chip attached to the first side of thesubstrate and electrically connected to the landing pad; wherein thesensor and the control chip each extend into the interior cavity; andwherein an air gap is disposed between the sensor and the control chip.22. The device of claim 21, wherein the sensor is at least partlylaterally aligned over the control chip.
 23. The device of claim 21,wherein the interconnect is a wirebond interconnect, and wherein thefirst end of the interconnect is a ball end.
 24. The device of claim 21,further comprising a sidewall disposed on the substrate with a first endof the sidewall affixed to the substrate, wherein the sidewall isconductive, and wherein the lid comprises a conductive material.
 25. Thedevice of claim 24, wherein the sidewall is a side portion of the lid.26. The device of claim 21, wherein the lid has at least one port.